The present invention relates to a magnetic tape library apparatus for automatically loading/unloading and storing a plurality of cartridge type magnetic tapes (will be referred to as tape cartridges hereinafter) and recording/reproducing data to/from the tape cartridges.
Conventionally, the tape cartridge has been well known as a medium for recording data. However, the tape cartridge is limited in volume of recording area, so that the tape cartridge is also limited in capacity of recording data. Therefore, a number of tape cartridges are required for a computer system such as a calculating system or a data base frame system to record a large quantity of indispensable data. In addition, a user of the computer system must change, namely, insert/eject many tape cartridges to a recording/reproducing apparatus in order to retrieve data. Needless to say, this puts the user to a great deal of inconvenience.
Therefore, the magnetic tape library apparatus for automatically loading/unloading and storing a plurality of tape cartridges and recording/reproducing data to/from the tape cartridges has been proposed and used.
Generally, the magnetic tape library apparatus comprises a cartridge storage shelf for storing a plurality of tape cartridges, a data recording/reproducing unit for recording/reproducing data to/from the tape cartridge, an entry mechanism for inserting/ejecting the tape cartridge into/from the magnetic tape library apparatus, and an access mechanism for transferring the tape cartridge between the cartridge storage shelf and the data recording/reproducing unit in the magnetic tape library apparatus. Furthermore, the magnetic tape library apparatus has a case for containing the cartridge storage shelf, the data recording/reproducing unit, the entry mechanism, the access mechanism, and so on. The case has (or is defined by) width, height, and depth directions which orthogonally cross at right angle to one another.
The cartridge storage shelf stores the tape cartridges so that the tape cartridges are arranged in the height direction in the case. The data recording/reproducing unit is arranged so as to adjoin the cartridge storage shelf in the height direction. The access mechanism transfers the tape cartridge in the height direction so that the tape cartridge is transferred between the cartridge storage shelf and the data recording/reproducing unit. The entry mechanism inserts/ejects the tape cartridge through access mechanism into/from the magnetic tape library apparatus. The entry mechanism transfers the tape cartridge in the depth direction.
Conventionally, the access and the entry mechanisms are independently comprised, as two units apart from each other, in the magnetic tape library apparatus.
The entry unit apart from the access unit is provided with an entry rack for temporarily holding the tape cartridge and a horizontal transferring mechanism portion for transferring the entry rack holding the tape cartridge in the depth direction so that the tape cartridge is transferred between the user and the access unit.
However, the conventional magnetic tape library apparatus needs a relatively wide space for arranging the entry rack and the horizontal transferring mechanism portion of the entry unit in the case. Therefore, the conventional magnetic tape library apparatus is enlarged in size. Furthermore, because the tape cartridge must be temporarily stored in the entry rack when the tape cartridge is inserted/ejected into/from the apparatus, the conventional magnetic tape library apparatus needs a relative long time duration for loading/unloading the tape cartridge.
It is therefore an object of the present invention to provide a magnetic tape library apparatus which has a small size.
It is another object of the present invention to provide a magnetic tape library apparatus which can load/unload the tape cartridge in high speed.
The other objects, features, and advantages of the present invention will become clear as the following description proceeds.
The present invention is directed to a magnetic tape library apparatus comprising a cartridge storage shelf for storing a plurality of tape cartridges, a data recording/reproducing unit for recording/reproducing data to/from the tape cartridge, an entry mechanism for inserting/ejecting the tape cartridge into/from the magnetic tape library apparatus, and an access mechanism for transferring the tape cartridge between the cartridge storage shelf and the data recording/reproducing unit. The entry and the access mechanisms are structured into a single body so as to serve as only an access unit.